SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe02f806d6208d33cfd330ea6da691f16bf5efd503b43881b39f32f6fe2cfba5' 
  AND token = 'PKfijvHZsTYW8UZ777e1F3Z3qX6JxVfiKgVmQuaKKrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}